I'm nervous about posting this, because it sounds so much like a user error
somewhere.

I've just replaced a combi with a system boiler and indirect cylinder, and
for various reasons decided to go for a W type arrangement with a diverter
rather than mid position valve.

So I have a new Honeywell V4044 in position, not yet wired in electrically
to the control box. No cylinder thermostat control yet, just running both
circuits at whatever the boiler supplies.

Boiler flow goes to AB, A goes to radiators, B goes to cylinder.

On the manual setting (for filling, flushing, etc) I get heat to both
circuits. With it set to auto and *no* electrical power to the valve, I get
flow to the cylinder but not to the radiators. With the valve *energised*, I
get flow to the radiators. (I'm not sure if there is flow to the cylinder in
this condition because it's a well insulated vertical run, so stays hot for
a while).

It's as if the ports are incorrectly labelled, which just seems incredibly
unlikely. But before breaking into the wet side to look, I just thought I
would say:

HELP!

On 18/11/2010 08:17, newshound wrote:

Boiler flow goes to AB, A goes to radiators, B goes to cylinder.

On the manual setting (for filling, flushing, etc) I get heat to both
circuits. With it set to auto and *no* electrical power to the valve, I
get flow to the cylinder but not to the radiators. With the valve
*energised*, I get flow to the radiators.

Then it's doing what it should, isn't it? The V4044 data sheet says

"Valve opens to Port A [...] under power[...]
"valve opens to port B [...] under spring return"

If you want flow to the cylinder when powered you need A to the cyl and
B to the rads.

--
Andy

"Andy Wade" wrote in message
...
On 18/11/2010 08:17, newshound wrote:

Boiler flow goes to AB, A goes to radiators, B goes to cylinder.

On the manual setting (for filling, flushing, etc) I get heat to both
circuits. With it set to auto and *no* electrical power to the valve, I
get flow to the cylinder but not to the radiators. With the valve
*energised*, I get flow to the radiators.

Then it's doing what it should, isn't it? The V4044 data sheet says

"Valve opens to Port A [...] under power[...]
"valve opens to port B [...] under spring return"

If you want flow to the cylinder when powered you need A to the cyl and B
to the rads.

--
Andy

Oh. The data sheet that came with it doesn't say anything about which way
round it goes under power. But you are absolutely right, the V4044 sheet on
the web does say "opens to A under power".

I *thought* I had read that you want "power on" to be the less frequent
condition with "power off" as the default. This would be consistent with the
rads as the normal condition, with the cylinder heated only when the
thermostat says it needs to be. My controller gives me power when the
cylinder thermostat says the cylinder is under-temperature.

The data sheet that came with my V4044C definitely says B to the cylinder, A
to the rads. So I fitted it that way without thinking any more about it.

Problem solved! At least now I don't have to take it off to experiment, I
can just swivel it round, hopefully without losing too much water. Thanks
for the quick response.

Steve

"newshound" wrote in message
...


"Andy Wade" wrote in message
...
On 18/11/2010 08:17, newshound wrote:

Boiler flow goes to AB, A goes to radiators, B goes to cylinder.

On the manual setting (for filling, flushing, etc) I get heat to both
circuits. With it set to auto and *no* electrical power to the valve, I
get flow to the cylinder but not to the radiators. With the valve
*energised*, I get flow to the radiators.

Then it's doing what it should, isn't it? The V4044 data sheet says

"Valve opens to Port A [...] under power[...]
"valve opens to port B [...] under spring return"

If you want flow to the cylinder when powered you need A to the cyl and B
to the rads.

--
Andy

Oh. The data sheet that came with it doesn't say anything about which way
round it goes under power. But you are absolutely right, the V4044 sheet
on the web does say "opens to A under power".

I *thought* I had read that you want "power on" to be the less frequent
condition with "power off" as the default. This would be consistent with
the rads as the normal condition, with the cylinder heated only when the
thermostat says it needs to be. My controller gives me power when the
cylinder thermostat says the cylinder is under-temperature.

The data sheet that came with my V4044C definitely says B to the cylinder,
A to the rads. So I fitted it that way without thinking any more about it.

Problem solved! At least now I don't have to take it off to experiment, I
can just swivel it round, hopefully without losing too much water. Thanks
for the quick response.

Steve

Surely you want to leave it like it is, otherwise your cylinder takes
preference over your heating doesn't it?

So with a cold system, and a cold house, you won't get any heat to the rads
until the cylinder is satisfied, or the thermostat on the cylinder is turned
off/down!?

--
Toby...
Remove pants to reply

newshound wrote:
"Andy Wade" wrote in message
...
On 18/11/2010 08:17, newshound wrote:

Boiler flow goes to AB, A goes to radiators, B goes to cylinder.

On the manual setting (for filling, flushing, etc) I get heat to
both circuits. With it set to auto and *no* electrical power to the
valve, I get flow to the cylinder but not to the radiators. With
the valve *energised*, I get flow to the radiators.

Then it's doing what it should, isn't it? The V4044 data sheet says

"Valve opens to Port A [...] under power[...]
"valve opens to port B [...] under spring return"

If you want flow to the cylinder when powered you need A to the cyl
and B to the rads.

--
Andy

Oh. The data sheet that came with it doesn't say anything about which
way round it goes under power. But you are absolutely right, the
V4044 sheet on the web does say "opens to A under power".

I *thought* I had read that you want "power on" to be the less
frequent condition with "power off" as the default. This would be
consistent with the rads as the normal condition, with the cylinder
heated only when the thermostat says it needs to be. My controller
gives me power when the cylinder thermostat says the cylinder is
under-temperature.
The data sheet that came with my V4044C definitely says B to the
cylinder, A to the rads. So I fitted it that way without thinking any
more about it.
Problem solved! At least now I don't have to take it off to
experiment, I can just swivel it round, hopefully without losing too
much water. Thanks for the quick response.

Do not swap it round. Port B is for the HW.

http://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Controls_and_Zonin g#DHW_priority:_W-Plan

--
Adam

Thanks to all for the helpful comments, I knew the collective brainpower
would sort me out (and I was right to be worried about posting my
incompetence).

To explain how I got into this position, I decided to go for W plan as I
have a rapid recovery cylinder and an old house with high thermal inertia:
so losing radiator heating while recovering the cylinder on occasions of
heavy hot water demand didn't seem like a problem. Also the diverter valve
seemed a little simpler and perhaps more reliable than a mid-position.

I went for a Vaillant boiler with their fancy electronic 140 timeswitch
which needs the VR 65 control unit. The timeswitch tells this what to do via
a low voltage link (described as a bus, so presumably some sort of digital
link). I hadn't been able to find the datasheet for that on the web at the
planning stage, so I didn't realise until the hardware arrived that it
notionally only supports Y-plan (mid position) or S-plan (zone valve)
systems, and not W plan. But by then I had a diverter rather than
mid-position valve plumbed in as described with B (closed on power) to the
cylinder and A (open on power) to the radiators.

But I thought never mind, I can ignore the timer-controlled supply which
opens the CH side and use the S plan timer controlled DHW supply to actuate
the diverter valve. That was when I thought the diverter valve OPENED to B
on power.

In the summer, I'll have a timer program to provide DHW only so that on a
cylinder thermostat demand, the boiler will power up and the diverter valve
will operate so I'm only heating the cylinder. In the winter, I'll have a
different program calling for CH and DHW so timed CH demand will heat the
rads except when there is a DHW demand as well, at which time diverter valve
will operate until the demand is satisfied, in other words W plan logic.

I have TRVs throughout except for a towel rail, but the new boiler has an
automatic bypass and fancy protection so I guess I could put that on TRV as
well.

Or am I still really missing something? For the case where I have a cold
house and a cold cylinder I suppose I could have another program for CH only
although, to be honest, that's probably where I would fire up the woodburner
and be wanting hot water ASAP.

"newshound" wrote in message
...

Thanks to all for the helpful comments, I knew the collective brainpower
would sort me out (and I was right to be worried about posting my
incompetence).

To explain how I got into this position, I decided to go for W plan as I
have a rapid recovery cylinder and an old house with high thermal inertia:
so losing radiator heating while recovering the cylinder on occasions of
heavy hot water demand didn't seem like a problem. Also the diverter valve
seemed a little simpler and perhaps more reliable than a mid-position.

I went for a Vaillant boiler with their fancy electronic 140 timeswitch
which needs the VR 65 control unit. The timeswitch tells this what to do
via a low voltage link (described as a bus, so presumably some sort of
digital link). I hadn't been able to find the datasheet for that on the
web at the planning stage, so I didn't realise until the hardware arrived
that it notionally only supports Y-plan (mid position) or S-plan (zone
valve) systems, and not W plan. But by then I had a diverter rather than
mid-position valve plumbed in as described with B (closed on power) to the
cylinder and A (open on power) to the radiators.

But I thought never mind, I can ignore the timer-controlled supply which
opens the CH side and use the S plan timer controlled DHW supply to
actuate the diverter valve. That was when I thought the diverter valve
OPENED to B on power.

In the summer, I'll have a timer program to provide DHW only so that on a
cylinder thermostat demand, the boiler will power up and the diverter
valve will operate so I'm only heating the cylinder. In the winter, I'll
have a different program calling for CH and DHW so timed CH demand will
heat the rads except when there is a DHW demand as well, at which time
diverter valve will operate until the demand is satisfied, in other words
W plan logic.

I have TRVs throughout except for a towel rail, but the new boiler has an
automatic bypass and fancy protection so I guess I could put that on TRV
as well.

Or am I still really missing something? For the case where I have a cold
house and a cold cylinder I suppose I could have another program for CH
only although, to be honest, that's probably where I would fire up the
woodburner and be wanting hot water ASAP.


So if you turn the divertor valve around and power it from the DHW ON
connection in the V65 it would do what you want.

If you then call for HW then the valve will open and you will heat your HW.
If you call for CH and HW then the valve will open heat up the HW until the
cylinder stat reaches temperature at which point your CH will be on.

And if you just call for CH you will get just CH.

Adam

On Nov 20, 11:48*am, "ARWadsworth"
wrote:
So if you turn the divertor valve around and power it from the DHW ON
connection in the V65 it would do what you want.

If you then call for HW then the valve will open and you will heat your HW.
If you call for CH and HW then the valve will open heat up the HW until the
cylinder stat reaches temperature at which point your CH will be on.

And if you just call for CH you will get just CH.
Yes and that approach will save a few watts for the motor and also
increase the lifespan of the valve since the alternative is to power
up the valve when the radiators are calling which will be many times
more than the cylinder is calling if its a high recovery variety.

Y plan is the same in that the default open port is B to cylinder.
This means the valve is energised/stalled when the radiators are
calling. Reversing the logic would work but cause the next person to
fix it to complain it was wired incorrectly in the first place. Of
course the standard way means ££ to repairers for replacing and more
money to the manufacturers and so keeps the wheels of industry
turning.

Dave.

"Dave Starling" wrote in message
...
On Nov 20, 11:48 am, "ARWadsworth"
wrote:
So if you turn the divertor valve around and power it from the DHW ON
connection in the V65 it would do what you want.

If you then call for HW then the valve will open and you will heat your
HW.
If you call for CH and HW then the valve will open heat up the HW until
the
cylinder stat reaches temperature at which point your CH will be on.

And if you just call for CH you will get just CH.
Yes and that approach will save a few watts for the motor and also
increase the lifespan of the valve since the alternative is to power
up the valve when the radiators are calling which will be many times
more than the cylinder is calling if its a high recovery variety.

Y plan is the same in that the default open port is B to cylinder.
This means the valve is energised/stalled when the radiators are
calling. Reversing the logic would work but cause the next person to
fix it to complain it was wired incorrectly in the first place. Of
course the standard way means ££ to repairers for replacing and more
money to the manufacturers and so keeps the wheels of industry
turning.

Dave.


Thank you both for the confirmation; that was just what I figured, I
implemented it yesterday and it seems just fine. And being a nice sort of
person, I'll write up a little note and leave it inside the VR65 box for any
future investigator!

Dave Starling wrote:

On Nov 20, 11:48 am, "ARWadsworth"
wrote:
So if you turn the divertor valve around and power it from the DHW ON
connection in the V65 it would do what you want.

If you then call for HW then the valve will open and you will heat your
HW. If you call for CH and HW then the valve will open heat up the HW
until the cylinder stat reaches temperature at which point your CH will
be on.

And if you just call for CH you will get just CH.
Yes and that approach will save a few watts for the motor and also
increase the lifespan of the valve since the alternative is to power
up the valve when the radiators are calling which will be many times
more than the cylinder is calling if its a high recovery variety.

I agree, it's a much better option for the valve to be actuated for HW
and unpowered for CH. One particular reason for this is that in summer,
when the CH is likely to be off for months on end, with the boiler firing
up only when HW is demanded (which typically it is likely to do at least
once a day), this will keep diverter valve exercised, and less likely
to stick through non-use.

Y plan is the same in that the default open port is B to cylinder.
This means the valve is energised/stalled when the radiators are
calling. Reversing the logic would work but cause the next person to
fix it to complain it was wired incorrectly in the first place.

Whether it's wired "correctly" is partly a question of whether the
plan to which it's wired is appropriate. A repairers mistake would
be to assume that the plan in question is "standard" W-plan. Clearly
if a more appropriate but less conventional plan is being used, it's
be a good idea to place a diagram of the system (as it is) into the
wiring box, together with a notice drawing attention to the fact that
it may be "nonstandard".

Of
course the standard way means ££ to repairers for replacing and more
money to the manufacturers and so keeps the wheels of industry
turning.

You're an old cynic, but absolutely right!